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freebsd/usr.sbin/chkgrp/chkgrp.c
Colin Percival a2c16fbcd0 Fix a bug introduced in revision 1.9 which causes chkgrp to coredump on
certain corrupt files.

Submitted by:	liamfoy@dragonflybsd.org
Reported by:	Nikolay Kalev, via freebsd-current
MFC after:	3 days
2005-08-25 17:01:06 +00:00

170 lines
4.4 KiB
C

/*-
* Copyright (c) 1998 Dag-Erling Coïdan Smørgrav
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <err.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
static char empty[] = { 0 };
static void
usage(void)
{
fprintf(stderr, "usage: chkgrp [groupfile]\n");
exit(EX_USAGE);
}
int
main(int argc, char *argv[])
{
unsigned int i;
size_t len;
int n = 0, k, e = 0;
char *line, *f[4], *p;
const char *cp, *gfn;
FILE *gf;
/* check arguments */
switch (argc) {
case 1:
gfn = "/etc/group";
break;
case 2:
gfn = argv[1];
break;
default:
gfn = NULL; /* silence compiler */
usage();
}
/* open group file */
if ((gf = fopen(gfn, "r")) == NULL)
err(EX_IOERR, "%s", gfn); /* XXX - is IO_ERR the correct exit code? */
/* check line by line */
while (++n) {
if ((line = fgetln(gf, &len)) == NULL)
break;
if (len > 0 && line[len - 1] != '\n') {
warnx("%s: line %d: no newline character", gfn, n);
e++;
}
while (len && isspace(line[len-1]))
len--;
/* ignore blank lines and comments */
for (p = line; p < (line + len); p++)
if (!isspace(*p)) break;
if (!len || (*p == '#')) {
#if 0
/* entry is correct, so print it */
printf("%*.*s\n", len, len, line);
#endif
continue;
}
/*
* A correct group entry has four colon-separated fields, the third
* of which must be entirely numeric and the fourth of which may
* be empty.
*/
for (i = k = 0; k < 4; k++) {
for (f[k] = line+i; (i < len) && (line[i] != ':'); i++)
/* nothing */ ;
if ((k < 3) && (line[i] != ':'))
break;
line[i++] = 0;
}
if (k < 4) {
warnx("%s: line %d: missing field(s)", gfn, n);
for ( ; k < 4; k++)
f[k] = empty;
e++;
}
for (cp = f[0] ; *cp ; cp++) {
if (!isalnum(*cp) && *cp != '.' && *cp != '_' && *cp != '-' &&
(cp > f[0] || *cp != '+')) {
warnx("%s: line %d: '%c' invalid character", gfn, n, *cp);
e++;
}
}
for (cp = f[3] ; *cp ; cp++) {
if (!isalnum(*cp) && *cp != '.' && *cp != '_' && *cp != '-' &&
*cp != ',') {
warnx("%s: line %d: '%c' invalid character", gfn, n, *cp);
e++;
}
}
/* check if fourth field ended with a colon */
if (i < len) {
warnx("%s: line %d: too many fields", gfn, n);
e++;
}
/* check that none of the fields contain whitespace */
for (k = 0; k < 4; k++) {
if (strcspn(f[k], " \t") != strlen(f[k])) {
warnx("%s: line %d: field %d contains whitespace",
gfn, n, k+1);
e++;
}
}
/* check that the GID is numeric */
if (strspn(f[2], "0123456789") != strlen(f[2])) {
warnx("%s: line %d: GID is not numeric", gfn, n);
e++;
}
#if 0
/* entry is correct, so print it */
printf("%s:%s:%s:%s\n", f[0], f[1], f[2], f[3]);
#endif
}
/* check what broke the loop */
if (ferror(gf))
err(EX_IOERR, "%s: line %d", gfn, n);
/* done */
fclose(gf);
if (e == 0)
printf("%s is fine\n", gfn);
exit(e ? EX_DATAERR : EX_OK);
}